Refs #9912: applied proposed patch of Micha Glave, but changed it a bit, because for compat reasons, table column 'summary' is added on upgrade from version 3 to 4. Please, test this commit and report if it still works with MySQL.

0.2dev: Copied _fixup_cc_list from the Trac core (trac.ticket.model) to replace the simplify_whitespace function. The CC list is now cleaned up on database insert. Previously, it would only be 'simplified' on Component creation, but not on Component edit. Removed instance of calling simplify_whitespace on the Component name variable. It seemed to be a misplaced call, which was probably intended for the cc variable.

0.2dev: Refs #4919: Modify CC list at the time of ticket creation, rather than after the ticket is created. This avoids an immediate comment change and email notification. Strip leading and trailing whitespace from the ticket. Thanks to Pete Suter with hints on the implementation.

This introduces a new option internal_css for the equally new upstream
configuration section wikicalendar. False is the default and that's fine,
unless you really need to force reading CSS style definitions.

I tried with ITemplateStreamFilter, but had to learn, that wiki macros are
expanded only afterwards, so including style definitions into the HTML page
seems like the only alternative to trac.web.chrome.add_stylesheet() so far.

FIX: Traceback would occur when a system_message is raised, which could be due to component with same name already existing or 'Remove selected items' pressed with no items selected. Thanks to nike-17@… for the report.

FIX: Package was missing __init__.py file, which could result in a failure of the plugin to load.

FIX: Removed rollbacks on db upgrade, which fail in Trac 1.0dev and later since the db connection is read-only.